Terminal lugs



y 1961 M. c. LOGAN 2,984,818

TERMINAL LUGS Filed March 15, 1959 INVENTOR. MA ueus C. L OGAN' United States Patent 2,984,818 I TERMINAL LUGS Maurus C. Logan, Elizabeth, N.J., assignor to The Thomas & Betts C0,, Elizabeth, N.J., a corporation of New Jersey Filed Mar. 13, 1959, Ser. No. 799,133

2 Claims. (Cl. 339-472) The invention relates to terminal lugs and more particularly to terminal lugs of the character adapted to be secured to or form an integral part of distribution panels, fuse boxes, circuit breakers and various types of switches adapted for carrying 100 ampere electric current service.

More specifically, the invention resides in a terminal lug of the set-screw type which is adapted for terminating a bare end portion of a multi-strand conductor or single wire conductor in fixed relation thereto, wherein a conductor receiving bore extending through the lug is provided with an integral rib or equivalent disposed lengthwise thereof and diametrically opposite the axial center of a transverse set-screw receiving bore, whereby in securing a single, relatively small diameter wire conductor in the here by means of the set-screw, the rib will maintain the conductor on either side of the axial center of the bearing end of the set-screw where it will be engaged by the conical bearing surface of the set-screw at a point between its axial center and outer periphery thereof.

Terminal lugs of this character as known heretofore, possessed certain disadvantages in that, when a bare end portion of a single wire insulated conductor was secured in its bore, it was apt to be clamped directly under the center-point of the conical bearing end of the set-screw and thus improperly secured and/or deformed in crosssection or otherwise impaired.

Accordingly, it is an object of the invention to provide an improved terminal lug of the character specified which obviates the aforesaid disadvantages.

Another object of the invention is to provide a terminal lug as specified in which a stripped end portion of insulated single wire conductors, as well as multi-strand conductors, may be properly secured at all times without undue deformation of its normal configuration in crosssection or otherwise weakened or impaired.

A further object of the invention is to provide a terminal lug of the character specified which does not present a problem in properly securing an end portion of a single wire conductor therein when located in inaccessible places as in small enclosures and the like.

Another object of the invention is to provide a terminal lug of the character specified which is also adapted for approved contact with the internal as well as the external strands of a multi-strand cable conductor when secured therein by means of its set-screw.

The invention, both as to its mode of operation and construction, may be understood from the following description when read together with the accompanying drawing, in which:

Fig. 1 is an end view in elevation of the improved terminal lug per se, showing a rib in its bore in direct alignment with the axial center of its set-screw;

Fig. 2 is a side view in elevation showing the improved terminal lug as secured, for example, on a distribution panel or the like;

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Fig. 3 is a vertical sectional view taken on the line 3--3 of Fig. 1;

Fig. 4 is an end view in elevation showing the improved terminal lug as mounted on a panel and a stripped end portion of a single wire conductor secured therein by the conical bearing end of its =set-screw to one side of its apex;

Fig. 5 is an end view similar to that of Fig. 4, and showing the bare end portion of a multi-strand cable conductor as secured therein by the conical bearing end of the set-screw; and

Fig. 6 is a fragmentary perspective view of a modified form: of the improved terminal lug, wherein a row of spaced, teat-like projections are provided in the bore thereof in lieu of the linear rib as in Figs. 1 through 5.

Referring now to Figs. 1 through 5, the improved terminal lug 10 comprises a rectangular member 12 of highly conductive metal such as aluminum or copper, for example, having an open-ended central bore 14 therethrough chamfered at one end as at 16, and a set-screw 18 provided with a conical bearing end 20 adjustably threaded through one side thereof in alignment with the axial center of the bore 14 and at right angles theretO.

The side of the terminal lug 10 which is diametrically opposite the side in which the set-screw 18 is adjustably threaded is provided with a rectangular or round boss 22, having a screw-threaded aperture 24 therein at right angles to the bore 14, in communication therewith or terminating short thereof, as desired, whereby the terminal lug 10 is adapted to be seated and secured on a distribution panel 26, or the like, provided with a slot or opening corresponding to the boss 22, by means of a suitable machine screw 28, whereby the lug 10 is adapted for terminating a multi-strand electric cable conductor in its bore 14, from the chamfered end 16 thereof, and for securing the same in approved electrical contact therewith by means of the set-screw 18.

In accordance with the invention, a small linear rib 30 is formed on the peripheral surface defining the bore 14, lengthwise thereof and in diametrically opposite relation to the axial center of the set-screw 18, the rib 30 being of substantially inverted V-shape in cross-section, with its apex rounded, as best shown in Figs. 1 and 4, whereby a number 1 4 or larger size single Wire conductor 32, when inserted in and held on the bottom of the bore 14, will be located by the rib 30, on either side of the axial center of the set-screw 18. Thus, when the set-screw 18 is adjusted on the single wire conductor 32, its conical bearing face 20 will clamp thereon at a point somewhere between its apex and the outer periphery of its base, depending upon the size of the single wire conductor 32, as: best shown in Fig. 4, whereby contact of the apex of the bearing end 20 of the setscrew 18, on the periphery of the single wire conductors 32, is obviated.

While the improved terminal lug 10 is particularly adapted for the reception of small size single wire conductors, it is not limited thereto since the diameter of its conductor-receiving bore 14 is such that relatively large multi-strand cable conductors may also be intruded therein and secured by the set-screw 18, as shown at 34 in Fig. 5, wherein it will be observed that the conical bearing end 20 thereof will penetrate the intruded multistrand conductor and establish contact with at least some of its inner strands as Well as its outer strands and that the spread of the strands resulting therefrom will not escape the conical bearing surface 20 of the set-screw 18 by reason of the fact that the maximum outer diameter of the set-screw 18 is substantially equal to the diameter of the conductor-receiving bore 14.

6, wherein the conductor-receiving bore 14 in the terminal lug is provided with a row of spaced teat-like projections 36 in parallelism therewith and in diametrically opposite relation to the axial center of the set-screw 18, in lieu of the linear rib 30, shown in the preceding figures.

While practical embodiments of the invention which give satisfactory results have been illustrated and described, it is to be expressly understood that various other changes and modifications may be made therein which fairly fall within the scope of the claims appended hereto.

I claim:

. 1. A terminal lug adapted to be mounted on a fiat support having an opening therethrough, said lug comprising a rectangular block of highly conductive metal having an open-ended bore centrally therethrough, a setscrew provided with a conical bearing and adjustably threaded in said block in intersecting relation with said bore for securing electric conductors of varying diameter in said bore, a rib of inverted V-shape in cross-section projecting from the surface defining said bore and extending lengthwise thereof in diametrically opposite alignment with the axial center of said set-screw, said set-screw having its bearing end shaped to secure a single conductor wire against said rib and the adjacent portions of said bore, and cable conductors against the defining surface of said bore, and an internally screw threaded boss integral with and projecting from the bottom face of said rectangular block in coaxial alignment with said set-screw adapted to seat in the opening in said support, said boss including an adjustable screw for securing said lug on said support.

2. A terminal lug adapted to be secured on a flat sup port having a slot therethrough comprising a rectangular block of highly conductive metal having an openended bore centrally therethrough, a set-screw provided with a conical bearing end terminating in a rounded apex adjustably threaded in said block in intersecting relation with said bore for securing electric conductors of varying circular mil area therein, an upstanding rib of inverted V-shape in cross-section having a rounded apex integral with and projecting from the definingsurface of said bore and extending lengthwise thereof in diametrically opposite alignment with the axial center of said set-screw, said set screw having its bearing end shaped to secure a single conductor 'wire against said rib when disposed on either side thereof and the adjacent portions of said bore, and cable conductors against the defining surface of said bore, and an internally screw threaded rectangular boss integral with and projeting from the bottom face of said block in coaxial align ment with said set-screw adapted to be received in the slot in said support, said rectangular boss including an adjustable screw for securing said terminal lug to said support.

References Citedin the file of this patent UNITED STATES PATENTS 302,972 Bailey ...Q Aug. 5, 18 84 688,360 Stone Dec. 10, 1901 1,679,677 Milne Aug. 7, 1923 2,885,654 Norden May 5, 19159 FOREIGN PATENTS 453,748 Italy Dec. 14, 1949 

